The current ISO standards pertaining to the Concepts of System and Architecture express succinct definitions of these two key terms that lend themselves to practical application and can be understood through elementary mathematical foundations. The current work of the ISO/IEC Working Group 42 is seeking to refine and elaborate the existing standards. This position paper revisits the fundamental concepts underlying both of these key terms and offers an approach to: (i) refine and exemplify the term 'fundamental concepts' in the current ISO definition of Architecture, (ii) exploit existing standards for the term 'concept', and (iii) introduce a new concept, Architectural Structure, that can serve to unify the current terminology at a fundamental level. Precise elementary examples are used in to conceptualise the approach offered.